The process for recovery of copper metal values from ores and processing liquids by solvent extraction-electrowinning (hereinafter, "SX-EW") is well-known. Briefly, the process is carried out using a copper-beating aqueous solution which is obtained by dissolving (generally from an ore) the copper in an aqueous leach liquor, or by using a copper-bearing solution such as process effluent. The resulting solution of copper values is mixed with a water-immiscible organic solvent (e.g., kerosene) containing a water-insoluble ion exchange composition having selective affinity for the copper values. The ion exchange composition preferentially extracts the copper values from the aqueous solution. The aqueous and organic phases are separated. The aqueous solution, now copper-depleted, is usually referred to as "raffinate." The raffinate can be recycled as leach liquor (in a leaching process) or discarded (in a process such as recovery of copper from process effluent). The organic phase (which contains ion exchange composition and the extracted copper values) is usually referred to as "loaded organic." The desired copper values are removed from the loaded organic by mixing with an aqueous strip solution containing strong acid such as sulfuric, phosphoric, or perchloric acid, and having lower pH than the above copper-bearing aqueous solution. The aqueous strip solution extracts the desired copper values from the loaded organic. After separation of the organic and aqueous phases, the desired copper values are present in the aqueous strip solution. The resulting copper-rich aqueous strip solution is usually referred to as an "electrolyte" or "rich electrolyte." The copper-depleted organic phase is usually referred to as a "barren organic." The barren organic can be recycled.
Copper is recovered in purified form from the electrolyte by a technique known as "electrowinning" (hereafter sometimes referred to as "EW"). The electrowinning process typically involves plating the copper on copper starting sheets or stainless steel cathode mother blanks. The plating cycle usually takes about seven days to obtain a 100-pound cathode from each side of the mother blank. The cathodes are stripped mechanically from each side of the mother blank.
The manufacture of copper wire involves melting, casting and hot rolling these cathodes in a separate facility to produce copper rod which is normally 5/16-inch (7.94 mm) in diameter. This copper rod is then converted to copper wire, e.g., electrical wire. The first step in this process is the "rod breakdown" wherein the rod is cold drawn to about AWG #14. (1.628 mm). The intermediate wire after "rod breakdown" is further cold drawn to the final product size. During the cold drawing operation the wire can be periodically annealed.
The conventional method of copper wire production consumes much energy and requires extensive labor and capital costs. The melting, casting and hot rolling operations subject the product to oxidation and potential contamination from foreign materials such as refractory and roll materials which can subsequently cause problems to wire drawers generally in the form of wire breaks during drawing.
By virtue of the inventive process copper wire is produced in a simplified and less costly manner when compared to the prior art. The inventive process can utilize a copper source such as copper ore or copper-containing waste that is relatively impure. This process does not require use of the prior art steps of first making copper cathodes then melting, casting and hot rolling the cathodes to provide a copper rod feedstock. In one embodiment the production of a copper rod feedstock is not even necessary.